Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen, Denmark.
Amino Acids. 2012 Sep;43(3):1265-75. doi: 10.1007/s00726-011-1199-1. Epub 2011 Dec 27.
L-Arginine (L-Arg) is a conditionally essential amino acid and a natural constituent of dietary proteins. Studies in obese rats and type 2 diabetic humans have indicated that dietary supplementation with L-Arg can diminish gain in white adipose tissue (WAT) and improve insulin sensitivity. However, the effects of L-Arg on glucose homeostasis, body composition and energy metabolism remain unclear. In addition, no studies have, to our knowledge, examined whether L-Arg has beneficial effects as a dietary supplement in the mouse model. In the present study, we investigated the effects of L-Arg supplementation to male C57BL/6 mice on an array of physiological parameters. L-Arg supplemented mice were maintained on a low-protein diet and body composition, appetite regulation, glucose tolerance, insulin sensitivity and energy expenditure were evaluated. A significant reduction in epididymal WAT was observed in L-Arg supplemented mice compared with mice fed an isocaloric control diet. Surprisingly, the L-Arg supplemented animals were hyperphagic corresponding to a highly significant decrease in feed efficiency, as body weight developed in a similar pattern in both experimental groups. Glucose homeostasis experiments revealed a major effect of L-Arg supplementation on glucose tolerance and insulin sensitivity, interestingly, independent of a parallel regulation in whole-body adiposity. Increased L-Arg ingestion also raised energy expenditure; however, no concurrent effect on locomotor activity, substrate metabolism or expression of uncoupling proteins (UCP1 and UCP2) in adipose tissues was displayed. In conclusion, dietary L-Arg supplementation substantially affects an array of metabolic-associated parameters including a reduction in WAT, hyperphagia, improved insulin sensitivity and increased energy expenditure in mice fed a low-protein diet.
精氨酸（L-Arg）是一种条件必需氨基酸，也是膳食蛋白质的天然成分。肥胖大鼠和 2 型糖尿病人类的研究表明，膳食补充 L-Arg 可以减少白色脂肪组织（WAT）的增加，并提高胰岛素敏感性。然而，L-Arg 对葡萄糖稳态、身体成分和能量代谢的影响仍不清楚。此外，据我们所知，没有研究检查 L-Arg 是否作为膳食补充剂在小鼠模型中具有有益作用。在本研究中，我们研究了 L-Arg 补充对雄性 C57BL/6 小鼠一系列生理参数的影响。补充 L-Arg 的小鼠维持在低蛋白饮食，评估了身体成分、食欲调节、葡萄糖耐量、胰岛素敏感性和能量消耗。与喂食等热量对照饮食的小鼠相比，补充 L-Arg 的小鼠附睾 WAT 明显减少。令人惊讶的是，补充 L-Arg 的动物表现出多食症，对应的饲料效率显著降低，因为两组实验动物的体重增长模式相似。葡萄糖稳态实验表明 L-Arg 补充对葡萄糖耐量和胰岛素敏感性有重大影响，有趣的是，这与全身肥胖的平行调节无关。增加 L-Arg 摄入还会提高能量消耗；然而，在脂肪组织中没有显示出对运动活性、底物代谢或解偶联蛋白（UCP1 和 UCP2）表达的并发影响。总之，膳食 L-Arg 补充对包括 WAT 减少、多食症、胰岛素敏感性提高和低蛋白饮食喂养小鼠能量消耗增加在内的一系列与代谢相关的参数有显著影响。
